In a short season like this one, the thing most likely to eat a pumpkin crop in Newfoundland and Labrador is the calendar. Frost arrives before late fruit finishes, and the deadline is set by the day a flower opens, not the day the seed went in. Insects and storage rot take their share too. But the clock does the most damage, and it does it in a predictable stretch of late summer.
The short answer
Working back from the first frost
Environment and Climate Change Canada’s climate normals put the average first fall frost at the St. John’s airport station on October 17. That is a mean date, not a promise. In one year out of two the frost falls later than that, which also means it comes on or before that date in the other half. Treat October 17 as the middle of a window, never as a safe date.
Now work backwards. Pumpkins take 45 to 55 days to mature after flowering, according to Utah State University Extension. Count 45 days back from October 17 and you land around September 2. Count 55 days back and you land around August 23. So the latest a flower can open and still give a ripe pumpkin here is roughly August 23 to September 2, in a year when frost arrives on schedule. A flower that opens after that window is a gamble, and the fruit it sets is more likely to end up green than orange.
Give that date as a window, not a day, because both ends move. The 45 to 55 range is itself a range, and the frost date swings from year to year. If frost shows up ten days ahead of the mean, the flowering deadline slides ten days earlier with it.
The count starts at flowering. It does not start at seeding or transplanting. A seed planted in June has no 45-to-55-day clock running until the first female flower opens and gets pollinated. The source used here does not give a seed-to-flower time, so that stretch is yours to read off the seed packet or track in your own bed. Many gardeners get this wrong by adding 45 to 55 days to the sowing date and deciding they have plenty of room.
Why one station is not the whole province
The October 17 figure comes from a single station, St. John’s A. A province is not one climate. Northern and upland districts, and Labrador in general, run weeks behind that station, so their frost windows arrive earlier and the flowering deadline moves earlier with them. This page holds no published frost date for those districts, so if you garden outside the St. John’s area, shift your deadline earlier and check what your own nearest weather station records.
One more caution: the Canadian normals cover a different thirty-year span than the US figures used elsewhere on this site, so don’t line the two up as if they were measured the same way. The pumpkin itself should come off the vine with the stem attached, before frost. For the full ripening picture, see Will Pumpkins Ripen Before Frost in Newfoundland and Labrador?, and for the broader growing guide, Growing Pumpkins in Newfoundland and Labrador.
When to sow here
Sowing is where the season gets spent. The rule from Utah State University Extension is to sow when the soil reaches 65 F. That temperature is a soil reading, and it is not the last frost date. Soil lags the air by weeks. Here is the arithmetic, step by step.
- Start at the last spring frost. The average at St. John’s A is May 30. Again, a mean: in half of years the last frost comes later.
- Add the soil lag. Cold ground takes weeks to warm after the final frost, so 65 F soil arrives weeks after May 30. That puts a bare-ground sowing in June at the earliest. This page holds no published number for the lag, so push a soil thermometer a couple of inches down and read it rather than guessing from the calendar.
- Subtract what row covers buy. A row cover over the bed gains about two weeks. If bare soil would hit 65 F on June 20, a covered bed gets there around June 6. That date is only an illustration, and your own reading decides.
- Add the time from seed to first flower. Our source does not state it. Take it from the seed packet and add it to your sowing date.
- Check the result against the deadline. The first flower needs to open by roughly August 23 to September 2. A seed in the ground on June 15 has 69 days to get a flower open before August 23. If the packet’s seed-to-flower time runs longer than that, the plan fails on paper before a single seed is sown.
- Re-run it for your own district. Anywhere frost comes earlier than at St. John’s A, the deadline in step 5 moves earlier, and the sowing date has to move with it.
Notice what the list does not do. It never sets the sowing date equal to May 30, and it never counts 45 to 55 days from the sowing date. Those two shortcuts are how most late-season pumpkin plans go wrong. For a fuller look at the sowing side, see When to Sow Pumpkins in Newfoundland and Labrador.
What goes wrong here
A short season fails in a handful of repeatable ways. Each one has a remedy, and most of the remedies come down to counting days earlier than feels necessary.
- A late flower that never colors. The fruit set after the flowering window runs out never gets its 45 to 55 days before frost, and it stays green. Mark the date each fruit sets on a calendar. After roughly late August to early September, pinch off new blossoms and tiny fruit so the vine puts its energy into pumpkins that can still finish.
- A fruit caught by frost. Frost can arrive before the average date, since it falls later than October 17 in only half of years. Watch the forecast through late September and into October, and harvest with the stem attached before the cold night, not after it. If a fruit was already hit, do not count on a long storage life, and use it first.
- A vine that dies back before the skin hardens. When the foliage collapses early, the fruit is on its own. Don’t wait for the vine to finish the job. Cut the pumpkin with the stem attached and move it to a spot where it will not freeze. The ripening page linked above covers what happens to fruit finished off the vine.
- Seed sown into cold soil. Sowing on the last frost date is the earliest mistake, because the soil has not reached 65 F. Use a thermometer, and use a row cover if you want the two weeks it buys.
- A good pumpkin stored in the wrong place. A whole pumpkin keeps three to six months in a cool, dark spot between 45 and 50 F, according to University of Illinois Extension. It should be kept away from ripening fruit and vegetables such as apples, potatoes and tomatoes, because ripening fruit gives off a gas that ages the pumpkin. The porch next to the apple crate is the worst spot. Utah State University Extension says only to store pumpkins where they will not freeze, and gives no temperature or keeping time of its own. The 45 to 50 F range applies to a whole pumpkin only, and says nothing about a carved one.
- Insects. Squash bugs and cucumber beetles already have state pages on this site, so this page does not re-describe them. No Newfoundland and Labrador pest calendar is published here, so check those pages and local advice before assuming insects, rather than the clock, are the problem.
Common questions
Does the October 17 date mean my pumpkins are safe until then?
No. October 17 is the average first fall frost at the St. John’s A station, so in one year out of two the first frost comes later, and in the other half it comes on or before that day. Treat it as the middle of a window and harvest ahead of any frost in the forecast.
Do the 45 to 55 days count from seeding?
No, they count from flowering. Utah State University Extension gives 45 to 55 days to maturity after the flower opens. Adding that figure to a sowing date makes the whole calculation wrong, because the plant spends weeks growing vines before the first flower appears.
Is 65 F soil the same as the last frost date?
No. The soil lags the air by weeks, so 65 F soil comes well after the average May 30 last frost at St. John’s A. A row cover can gain about two weeks, but a soil thermometer gives the real answer for your bed.
Can I store a carved pumpkin the same way as a whole one?
No. The three to six months at 45 to 50 F, from University of Illinois Extension, applies to a whole pumpkin kept cool, dark and away from apples, potatoes and tomatoes. That source gives no storage time for a carved pumpkin, and neither does this page.